ALSA: compress: fix partial_drain completion state

On partial_drain completion we should be in SNDRV_PCM_STATE_RUNNING
state, so set that for partially draining streams in
snd_compr_drain_notify() and use a flag for partially draining streams

While at it, add locks for stream state change in
snd_compr_drain_notify() as well.

Fixes: f44f2a54 ("ALSA: compress: fix drain calls blocking other compress functions (v6)")
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20200629134737.105993-4-vkoul@kernel.orgSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/compress_driver.h

@@ -66,6 +66,7 @@ struct snd_compr_runtime {
  * @direction: stream direction, playback/recording
  * @metadata_set: metadata set flag, true when set
  * @next_track: has userspace signal next track transition, true when set
+ * @partial_drain: undergoing partial_drain for stream, true when set
  * @private_data: pointer to DSP private data
  * @dma_buffer: allocated buffer if any
  */
@@ -78,6 +79,7 @@ struct snd_compr_stream {
 	enum snd_compr_direction direction;
 	bool metadata_set;
 	bool next_track;
+	bool partial_drain;
 	void *private_data;
 	struct snd_dma_buffer dma_buffer;
 };
@@ -182,7 +184,13 @@ static inline void snd_compr_drain_notify(struct snd_compr_stream *stream)
 	if (snd_BUG_ON(!stream))
 		return;
 
+	/* for partial_drain case we are back to running state on success */
+	if (stream->partial_drain) {
+		stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
+		stream->partial_drain = false; /* clear this flag as well */
+	} else {
 		stream->runtime->state = SNDRV_PCM_STATE_SETUP;
+	}
 
 	wake_up(&stream->runtime->sleep);
 }

sound/core/compress_offload.c

@@ -764,6 +764,9 @@ static int snd_compr_stop(struct snd_compr_stream *stream)
 
 	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_STOP);
 	if (!retval) {
+		/* clear flags and stop any drain wait */
+		stream->partial_drain = false;
+		stream->metadata_set = false;
 		snd_compr_drain_notify(stream);
 		stream->runtime->total_bytes_available = 0;
 		stream->runtime->total_bytes_transferred = 0;
@@ -921,6 +924,7 @@ static int snd_compr_partial_drain(struct snd_compr_stream *stream)
 	if (stream->next_track == false)
 		return -EPERM;
 
+	stream->partial_drain = true;
 	retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_PARTIAL_DRAIN);
 	if (retval) {
 		pr_debug("Partial drain returned failure\n");